Dispenser mechanism

ABSTRACT

A dispenser mechanism ( 1 ) for a foamed product comprises a liquid chamber ( 9 ) and air chamber ( 10 ), each compressed by a common actuator mechanism ( 6   a,    6   b ), wherein the liquid and air simultaneously enter a foaming chamber ( 15 ). The liquid is forced through a diffuser ( 18   a ) defining a plurality of distributed channels ( 18   e ), each channel ( 18   e ) having a predetermined cross section such that in use the liquid is forced through the channels and enters the foaming chamber as a plurality of jets. The dispenser mechanism ( 1 ) provides a particularly advantageous arrangement for producing foam and may be arranged to prevent the foam dripping from an outlet after the end of a dispensing cycle.

The present invention relates to a dispenser mechanism for foamedproducts and particularly, but not exclusively, relates to dispensermechanisms for wall mounted soap dispensers.

Wall mounted soap dispensers traditionally dispense a liquid soap.However, with liquid soap it is necessary for the viscosity to be highenough that it can be applied to the hands without running off, enablingthe soap to cling to the hands while being conveyed from under thedispenser to over the sink Two problems associated with the highviscosity of liquid soaps is that it is necessary to dispense arelatively large quantity to enable the user to easily spread the soapover the surface of his hands and also this high viscosity tends toresult in a large quantity of the soap remaining in the outlet of thedispenser, which subsequently drips onto the surface or the floor below.

In an attempt to address the above problems, soap dispensers have beendeveloped which produce foam by mixing air with the liquid soap as it isdispensed. The action of operating the dispenser causes a soap productto be sprayed into a jet of air to produce the foam. The advantage ofthis is that a large quantity of foam can be produced from a relativelysmall volume of liquid soap, reducing the amount of liquid a userrequires to satisfactorily apply the soap over his hands. This reducesthe cost of product required and also the frequency with which thedispenser needs to be refilled. Thus foam dispensers overcome one of theproblems identified above associated with traditional liquid soapdispensers. However many foam dispensers still tend to drip as foamaccumulated in the nozzles reverts to a liquid causing the nozzle todrip. Additionally it is desirable that the dispenser mechanism iscompact and comprises a minimum of components so that it may berelatively expensive and therefore practical to produce a dispensermechanism which can be sold as part of the refill pack for a dispenser,thus the parts likely to fail are part of the disposable refill and canthus, in the event of a failure, can simply be replaced by replacing therefill pack.

It is an object of the present invention to provide an improveddispenser mechanism for foam products.

According to a first aspect of the present invention a dispensermechanism for a foamed product comprises: a liquid chamber arranged toreceive a liquid product; an air chamber arranged to receive air; anactuator mechanism; and a foaming chamber, the actuator mechanismcomprising a shaft, displacement of which simultaneously reduces thevolume of both the liquid and air chambers and forces the air and liquidwithin the respective chambers to enter the foaming chamber,characterised in that the foaming chamber is formed integrally withinthe shaft and in that a diffuser is located in the shaft through whichthe liquid enters the foaming chamber, the diffuser defining a pluralityof distributed channels, each channel having a predetermined crosssection such that in use the liquid is forced through the channels andenters the foaming chamber as a plurality of jets.

The invention permits efficient mixing of the liquid and air in a verycompact arrangement.

Preferably, the actuator mechanism comprises two pistons on a commonshaft, each piston acting on respective one of the liquid and airchambers, for in this way it is possible to have a dispenser mechanismwhich employs only one single moving part, which reduces costsassociated with manufacturer and thus is particularly beneficial if thedispensing mechanism is to be part of a disposable refill pack.

Advantageously, a first chamber is in the form of a cylinder in to whicha first one of the pistons extends to pressurise the contents of thechamber and wherein the foaming chamber is formed in the shaft, as thiscan provide a very compact arrangement.

Preferably, the actuator mechanism is biased to a rest position whereboth pistons are withdrawn to their maximum extent from their respectivechambers. When in the rest position, the liquid chamber can be sealed,preventing liquid seeping through the dispenser mechanism.

It is particularly advantageous if the action of the actuator mechanismreturning to its rest position sucks air into the air chamber via anoutlet of the dispenser mechanism, causing any foam remaining in theoutlet to be sucked back into the air chamber and thus preventing thefoam from reverting to a liquid in the outlet and dripping from theoutlet.

Advantageously, the liquid chamber has a one way valve to permit liquidto enter the chamber when the piston is withdrawn from the chamber,wherein the dispenser mechanism includes a transport cap arranged toprevent accidental operation of the actuator mechanism in transit, thetransport cap being arranged to keep the actuator mechanism in a fullydepressed position where the piston of the liquid chamber is in contactwith the one way valve and maintains it in a closed position. This maybe particularly advantageous where the dispensing mechanism is to besold as part of a disposable refill pack for assembly as a complete unitwithin a wall mounted housing. This can ensure that pressures applied tothe walls of the liquid container, which is normally a non-ventedcollapsible container, will not cause the liquid within the container toleak out via the dispenser mechanism.

The diffuser may have a plurality of recesses about its outer periphery,which recesses define with the inner wall of the shaft said plurality ofchannels. The recesses can then be formed in the moulding of an uppercomponent of the shaft, on which the diffuser is preferably integrallyformed. Alternatively the periphery of the diffuser may be smooth withridges or recesses formed on the inner wall of the shaft, such when thediffuser is located in the shaft, the diffuser and inner wall of theshaft together define said plurality of distributed channels.

As an alternative to the above described embodiments of the diffuser,the diffuser may instead comprise a rigid disc with a plurality ofapertures extending there through.

Preferably the shaft comprises an upper component and a lower component,each moulded as a single piece, wherein the upper component includes afirst piston and the diffuser, the lower component includes a secondpiston and an outlet passage of the mechanism. The upper component ofthe shaft may further comprise a retaining disc integrally moulded withthe first component, wherein an edge of the retaining disc and an innerwall of the shaft are arranged to engage with each other to lock theupper and lower components together. This enables the shaft to compriseonly two components that together form the two pistons, the mixingchamber and the diffuser, with the retainer enabling the two componentsto be assembled simply by snapping them together.

A dispenser mechanism in accordance with the invention is particularlyadvantageous in manually operated applications, such as soap dispensers.

Preferably, the dispenser mechanism further comprises a user interfacefor receiving a single stroke actuation by a user for dispensing apredetermined quantity of product to the user and a linkage mechanismfor transferring, on a full stroke of the dispenser mechanism, anydisplacement of the user interface to the dispensing mechanism, whereinthe linkage mechanism permits the user interface to be operated to thefull extent permitted by the interface and transmit only as much of theoperation of the interface to be transmitted to the dispenser mechanismas is required to permit the dispenser mechanism to dispense thepredetermined amount of product.

This mechanism is particularly advantageous for it can be arranged toensure that any reasonable exertion on the user interface causes thedispenser mechanism to operate fully and thus provide a desired volumeof product, while ensuring that any excessive pressure applied to theuser interface does not damage the dispenser mechanism. It can alsopermit a single dispenser case to be used with a range of products andproduct volumes without modification, or to allow a common dispensermechanism to be adjusted to provide different product volumes byadjusting the dispenser mechanism stroke length. It also prevents damageto the dispenser mechanism that occurs when the pump mechanism controlsthe actuation stroke of the dispenser interface.

Advantageously, the linkage mechanism comprises a resilient devicebetween the interface and dispenser mechanism, properties of theresilient device being sufficient to fully activate the dispensermechanism when the interface is sufficiently operated, but which absorbsany further movement of the interface to prevent damage to the dispensermechanism.

The invention is particularly applicable to soap dispensers arranged topermit single handed one stroke operation.

One embodiment of the present invention will now be described, by way ofexample only, with reference to the figures, in which like numerals areused throughout to indicate like parts, and in which:

FIG. 1 is a cross-section through a dispensing mechanism in accordancewith the present invention, with a transport cap in place;

FIG. 2 a is a corresponding cross-section to that of FIG. 1 but with thetransport cap removed;

FIG. 2 b is an enlarged scale view of the section labelled ‘X’ of FIG.2;

FIG. 2 c an enlarged scale section along the line A-A of FIG. 2;

FIG. 2 d an enlarged scale section along the line B-B of FIG. 2;

FIGS. 3 to 5 are sectional views corresponding to that of FIG. 2 a, butdepicting the dispensing mechanism at various stages of operation;

FIG. 6 a is a side elevation of the dispenser mechanism additionallyillustrating a user interface for the dispenser mechanism described withreference to FIGS. 1 to 8;

FIG. 6 b is a front sectional view of the dispenser of FIG. 6 a; and

FIGS. 7 a, 7 b, 8 a, 8 b, 9 a, 9 b, 10 a and 10 b, correspond to thoseof FIGS. 6 a and 6 b, but show the dispenser at various stages ofoperation in the dispensing cycle.

Referring to FIG. 1, there is illustrated a dispenser mechanism 1 inaccordance with the present invention connected to a disposablecollapsible container 2 filled with liquid soap 3. The container 2 anddispenser mechanism 1 together form a disposable refill pack for wallmounted soap dispensers.

The dispenser mechanism of FIG. 1 is transported attached to the filledcontainer 2 and the dispenser mechanism comprises a transport cap 4,secured to the housing 5 of the dispenser mechanism. This preventsaccidental actuation of the dispenser mechanism prior to installation ina dispenser, or leakage due to compression of the collapsible container2.

The dispenser mechanism has a shaft 6 comprising an upper component 6 aand a lower component 6 b, joined together such that in use there is norelative displacement between them. The upper component 6 a defines afirst piston 7 and the lower component 6 b defines a second piston 8.

The first piston 7, together with the housing 5, defines a first chamber9, with the second piston 8 defining with the housing 5 a second chamber10.

In the top of the first chamber 9 there is an opening, in which openingthere is located a non-return valve 11. When open, the non-return valve11 permits liquid soap 3 to flow from the container 2 to the firstchamber 9.

When the transport cap is in place, as shown in FIG. 1, the shaft 6 andassociated piston 7 and 8 are retained in a fully depressed, (raised),position whereby a pin 12, extending from the centre of the first piston7, engages with the non-return valve 11 to keep it in a closed position,as shown. This ensures that during transit, fluid cannot leak from thecontainer 3 through the dispenser mechanism 1.

Referring now to FIG. 2 a, a corresponding view to that of FIG. 1 isshown but with the transport cap 4 removed. When the transport cap isremoved and the dispenser mechanism installed in a dispenser (asdescribed below with reference to FIGS. 6 a to 10 b) the mechanism ofthe dispenser, not shown in FIG. 2 a, biases flange 13 located towardsthe bottom of lower component 6 b of the shaft 6 to the position shownin FIG. 2 a. In this position rubber O-ring seal 14 seals with the firstpiston 7 preventing the liquid soap 3 passing between the outer wall ofpiston 7 and the inner wall of the housing 5. The O-ring 14 is retainedin place by end cap 14 a. Drawing the shaft 6 downwards causes liquidsoap 3 to flow into the first chamber 9.

As most clearly seen in FIG. 2 b, the upper component 6 a of shaft 6 andthe lower component 6 b of shaft 6 define, at the lowermost portion ofthe component 6 a, channels 22 between the components 6 a and 6 b. Whenthe shaft 6 is raised by means of flange 13, air in the second chamber10 is compressed and passes through apertures 24 and channels 22 in thelower component 6 b, in the direction of arrows 25, to a mixing chamber15.

Referring again to FIG. 2 a, the upper component 6 a of the shaft 6additionally comprises two disc like members 18 a and 18 b. The upperdisc like member 18 b is a retainer and is shown in plan view in FIG. 2d, a section along the line A-A of FIG. 2 a. The retainer 18 b, formingpart of the upper component 6 a of shaft 6, has a narrow peripheral edgesection which engages in a circumferential slot in the inner wall of thelower component 6 b of the shaft 6. This locks the two components 6 aand 6 b together. Apertures 18 d in retainer 18 b permit fluid to passthere through, as described below.

The lower disc like member 18 a, of FIG. 2 a, is a diffuser and has anouter serrated edge 18 c. This edge together with the inner wall of thelower component 6 b of shaft 6 defines a plurality of channels, each ofa predetermined cross section, extending into a mixing chamber 15, alsodefined by the upper component and the inner wall of the lower component6 b of the shaft 6.

In the embodiment shown, the channels are formed by the serrated edge ofthe diffuser 18 a engaging the inner wall of component 6 b. However inalternative arrangements, the channels could be formed as distributedapertures through the diffuser 18 a, or the diffuser could have a smoothouter edge and the inner wall of component 6 b could have verticalridges thereon, which would, in combination with the edge of thediffuser 18 a, define the channels. Each arrangement permits liquid soapto be injected into the mixing chamber 15 via a number of distributedchannels, each of a predetermined cross section, which is not dependenton the pressure of the liquid soap passing there through, (representedby the arrows 3 b of FIG. 2 b and FIG. 3).

As seen from FIG. 3, when the shaft 6 is raised by the operation of thedispenser acting on flange 13 (relative to the position shown in FIG. 2a), the upper component 6 a of shaft 6 moves to a position where thepiston 6 is no longer sealed by the O-ring 14, permitting liquid soap 3,displaced by the action of the piston 7 entering the first chamber 9, tobe forced down the side of the first piston 7 through apertures 18 d ofthe retainer 18 b, and to enter into the channels 18 e of the diffusers18 a. The liquid 3 is sprayed under pressure as a plurality of jets fromthe channels into the mixing chamber 15. Simultaneously, air is forcedinto the mixing chamber in the direction of arrows 25 causing the airand liquid to intermingle before exiting the mixing chamber 15 as afoam, via apertures 6 d in the conical section 17 of the upper component6 a of shaft 6, as shown in FIG. 2 b.

As illustrated by FIGS. 2 a and 3, the foam passes in the direction ofarrows 27 down a central passage 19 formed by the lower component 6 b ofshaft 6 through a gauze 21, which aggregates the foam bubble size, tooutlet 20.

FIG. 4 is a corresponding view to FIG. 3 but shows the dispensermechanism when the shaft 6 is fully depressed (raised) and reaches thelimit of its travel.

FIG. 5 corresponds to FIG. 4, but shows the dispensing mechanism 1midway through its return stroke, the dispensing mechanism being actedupon by the dispenser (not shown) drawing flange 13 in the direction ofarrows 28 back to its rest position. During this part of the cycle, theexpanding volume within the second chamber 10 draws air into the secondchamber through the passage 19, channels 22 and apertures 23, asrepresented by arrows 29 and 30. This draws any foam remaining in thepassage 19 back into the bottom of the chamber 10, from where it will beexpelled back through the channels 22 to the mixing chamber 15 at thestart of the next dispensing cycle. This ensures that at the end of thedispensing cycle passage 19 is free of foam and thus will not drip asthe foam reverts back to liquid. With subsequent dispensing actions thevolume of liquid soap 3 within the container 2 will be reduced and thecontainer will collapse.

FIG. 6 a is a side elevation of a wall mounted liquid soap dispenser 31having an actuator handle 37 and FIG. 6 b is a front sectional viewthrough the dispenser 31. The dispenser 31 comprises a back plate 32providing mounting for the dispenser mechanism 1 of FIGS. 1 to 5, shownhere with an alternative type of collapsible container 2.

The dispenser 31 has a main pillars 33 which are constrained and run invertical bearing surfaces on the back plate 32. The pillars 33, locatedto either side of the dispenser, are attached to a main plate 34 asshown, with springs 35 acting between the main plate 33 and back plate32 maintaining the main plate 34 in its lower position as shown.

Slots 36 in each of the main pillars 33 engage with pegs (not shown) ofthe actuator handle 37 of FIG. 6 a, which handle provides a userinterface by which a user may operate the dispenser. A user pressing thehandle 37 causes the pegs of the handle to vertically raise the mainpillars 33.

A travelling plate 38 is attached by auxiliary pillars 39, whichauxiliary pillars 39 pass through holes in the main plate 33, withsprings 40 acting between a shoulder on the top of the auxiliary pillars39 and the main plate 34 to retain the travelling plate in an upperposition next to the main plate 34, as shown. The travelling plate 38 isalso attached to the flange 13 on the shaft 6 of the dispensingmechanism 1, such that the shaft 6 moves with the travelling plate 38.

Referring now to FIGS. 7 a and 7 b, these correspond to those of FIGS. 6a and 6 b but show the dispenser at full stroke, when the handle 37 hasbeen fully depressed and is restrained by stops associated with thehandle. The action of pressing the handle has raised the main pillars 33to the position shown, whereby this in turn has raised the main plate34, travelling plate 38 and shaft 6 to its fully raised position,dispensing a predetermined quantity of foam.

Referring to FIGS. 8 a and 8 b, there is shown the same dispenser 31fitted with an alternative dispensing mechanism 1 a which has a reducedoperating stroke. The dispensing mechanism la is fitted to the dispenser31, in the same manner as previously described with reference to FIGS. 6a to 7 b. However, as shown in corresponding FIGS. 9 a to 9 b, partialdepression of the handle 37 will complete a full stroke of the dispensermechanism. If the handle 37 was directly linked to the dispensermechanism 1 a, then further force depression of the handle 37, whichoften occurs as a user will commonly “thump” the handle, would result indamage to the dispenser mechanism. However, as illustrated in FIGS. 10 aand 10 b, further depression of the handle 37, to complete a full strokeof the handle, causes the travelling plate 38 to move away from the mainplate 34 against the force exerted by springs 40. Thus, the springs 40act as a resilient means absorbing the extra displacement. This permitsthe dispenser 31 to be used with dispenser mechanisms having differentfull stroke lengths or may be arranged to permit the stroke length ofthe dispensing mechanism to be varied in order to control the quantityof foam, or other product to be dispensed.

The embodiment described above is given by way of example only and thescope of the invention is to be determined with reference to theappended claims.

1. A dispenser mechanism for a foamed product comprises: a liquidchamber arranged to receive a liquid product; an air chamber arranged toreceive air; an actuator mechanism; and a foaming chamber, the actuatormechanism comprising a shaft, displacement of which simultaneouslyreduces the volume of both the liquid and air chambers and forces theair and liquid within the respective chambers to enter the foamingchamber, characterised in that the foaming chamber is formed integrallywithin the shaft and in that a diffuser is located in the shaft throughwhich the liquid enters the foaming chamber, the diffuser defining aplurality of distributed channels, each channel having a predeterminedcross section such that in use the liquid is forced through the channelsand enters the foaming chamber as a plurality of jets.
 2. A dispensermechanism as claimed in claim 1, wherein the actuator mechanismcomprises a first and a second piston located on the shaft, each pistonacting on a respective one of the liquid and air chambers.
 3. Adispenser mechanism as claimed in claim 2, wherein a first chamber is inthe form of a cylinder into which the first piston extends to pressurisethe contents of the chamber and wherein the foaming chamber is formed inthe shaft.
 4. A dispenser mechanism as claimed in claim 1, wherein theactuator mechanism is biased to a rest position where the pistonsassociated with each respective chamber are withdrawn to their maximumextent from their respective chambers.
 5. A dispenser mechanism asclaimed in claim 4, wherein in the rest position the liquid chamber issealed by its associated piston.
 6. A dispenser mechanism as claimed inclaim 4, wherein the action of the actuator mechanism returning to itsrest position sucks air into the air chamber via an outlet of thedispenser mechanism, causing any foam remaining in the outlet to besucked back into the air chamber.
 7. A dispenser mechanism as claimed inclaim 1, wherein the liquid chamber has a piston and a one way valve topermit liquid to enter the chamber when the piston is withdrawn from thechamber, wherein the dispenser mechanism includes a transport caparranged to prevent accidental operation of the actuator mechanism intransit and to keep the actuator mechanism in a fully depressed positionwhere the piston of the liquid chamber is in contact with the one wayvalve and maintains the valve in a closed position.
 8. A dispensermechanism as claimed in claim 1, wherein the diffuser is in the form ofa rigid disc located within the shaft, wherein the inner wall of theshaft and the diffuser define the plurality of distributed channels. 9.A dispenser mechanism as claimed in claim 8 wherein the diffuser hasrecesses about its outer periphery, which recesses define with the innerwall of the shaft said plurality of channels.
 10. A dispenser mechanismas claimed in claim 1, wherein the diffuser comprises a rigid disc witha plurality of apertures extending there through.
 11. A dispensermechanism as claimed in claim 1, wherein the shaft comprises an uppercomponent and a lower component, each moulded as a single piece, whereinthe upper component includes a first piston and a diffuser, the lowercomponent includes a second piston and an outlet passage of themechanism.
 12. A dispenser mechanism as claimed in claim 11, wherein theupper component of the shaft further comprises a retaining discintegrally moulded with the first component, an edge of the retainingdisc and an inner wall of the shaft being arranged to engage with eachother to lock the upper and lower components together.
 13. A dispensermechanism as claimed in claim 1, arranged to be manually operated.
 14. Adispenser mechanism as claimed in claim 1, further comprising a userinterface for receiving a single stroke actuation by a user, fordispensing a predetermined quantity of product to the user on a fullstroke of the dispenser mechanism and a linkage mechanism fortransferring any displacement of the user interface to the dispensingmechanism, wherein the linkage mechanism permits the user interface tobe operated to the full extent permitted by the interface and transmitto the dispenser mechanism only as much of the operation of theinterface as is required to permit the dispenser mechanism to dispensethe predetermined amount of product.
 15. A dispenser mechanism asclaimed in claim 14, wherein the linkage mechanism comprises a resilientdevice arranged between the interface and the dispenser mechanism, theproperties of the resilient device being such as to fully actuate thedispenser mechanism on operation of the interface but which resilientdevice absorbs any excess movement of the interface to prevent damage tothe dispenser mechanism.
 16. A dispenser mechanism as claimed in claim15, wherein the linkage mechanism comprises a first plate connected tothe user interface and arranged to move with the user interface, asecond plate connected to the dispenser mechanism, and at least oneresilient member arranged to act between the first plate and the secondplate, the resilient member being selected such that it will cause thetwo plates to be displaced together in response to any movement of theuser interface to cause the dispenser mechanism to be operated butwhich, when the dispenser mechanism reaches the end of its travel,permits the first plate to continue to be displaced whilst the secondplate remains substantially stationary.
 17. A dispenser mechanism asclaimed in claim 14 for dispensing soap and arranged to be wall mountedand permit single handed one stroke operation.
 18. A dispenser mechanismas claimed in claim 1, wherein reducing the volume of both the liquidand air chambers pressurises the contents of the chambers and the closedportion receives pressurised liquid from the liquid chamber and whereinthe liquid is forced under pressure through the channels.